Blackboard



UNITED STATES ATENT OFFICE.,

vWILLIAM n. MCKENZIn'oF ZIoNsvILLn, INDIANA.

BLACKBOARD I SPECIFICATION forming part of Letters Patent No. 323,350, dated July 28, 1885.

Application med January 16,1855. (No model.)

T0 all whom it may wwe-ern.- Y

Be it known that l', WILLIAM E. lVIoKnN-. ZIE, a residentyof Zionsville, Indiana, have made certain new and useful Improvements in Blackboards, a description of which is set forth in the following specication, reference being made to the accompanying drawings, in the several figures of whichlike letters indicate like parts.

My improvement consists in combining in a stationary frame a revolving frame which contains a series of blackboards adapted to slide in grooves in the revolving frame, and will be understood from the following descrip tion. Y

In the drawings, Figure 1 represents a isometric view of my device. Fig. 2 represents a cross-section on the line x Fig. 3 represents a top view, the revolving frame being swung around so as to be substantially at right angles to the stationary frame.

In detail, j' f is a stationary frame resting `upon two feet, the cross-pieces of such frame having tenons entering the uprights through mortises and secured by keys k, for the purpose of allowing this stationary frame to. be taken apart and compactly packed for shipment.

r fis a revolving tranne, which is adapted, by means of pivots 19 on its ends which have bearings in socket-plates s attached to the top and bottom cross-pieces V,of the stationary frame, to revolve in such stationary frame, and it may be locked in position by means of the catch c.

b b are blackboards, which'are fitted to slide easily in the grooves g, formed in the sides of the uprights of the revolving frame. This revolving frame may be made wide enough to allow a series of grooves to be made on the inside of :its uprights, and a separate boards fitted to slide in each one of these grooves.4

The boards are made about half the height of the revolving frame, so that Vtwo boards will fill its opening, and when one side of one or more boards has been used, by revolving the frame 011 its pivots the other side of the board will be presented for use. When one board has been filled with work, it may be pushed down in its groove and another board raised,

so on, successively, until all are used. By providing a number of these boards in the same frame, a series of lessons once put upon the boards may be preserved for some time. Thus, if siX boards are used, they will carry twelvelessons, and by this means the teacherv Awill vbe enabled to present them successively for review without being compelled to re-Write them upon the boards.

n c 71. is a grooved strip or box for holding chalk.

I ain aware that revolving blackboards are Y not new, and that blackboards adapted to slide in grooves in frames are not new, and do not broadly claim such as my invention; but I am not aware that any blackboard has been "made prior to my invention, wherein a frame adapted to revolve upon pivots Within the stationary frame has also been provided with grooves in which blackboards are made to slide, as shown in my device.

Maps or diagrams may, of course, be either temporarily or permanently put upon the sliding boards of my device, and they may be used for such purposes, as well as for ordinary blackboards.

When a board is shoved up to the top of the revolving frame, it may be secured in that position by means of a catch or pin, or any other suitable device.

What I claim, and desire to secure by Letters `Patent, is

1. A lesson-board wherein a revolving frame containing two or more boards adapted to slide in grooves formed in the sides of such revolving frame is adapted to revolve on pivots having bearings in an outside stationary frame, substantially as described.

2. In a lesson-board, the stationary frame f f, the revolving frame r f, having pivots p, adaptedto revolve in socket-plates attached to the stationary frame, the boards b, adapted to slide in grooves g on the inside of the re= .volving frame, and the catch o, for-locking such revolving frame in place, all combined substantially as described.

3. In a lessonboard, the vstationary frame ff, its parts secured by keys 7c, the frame rj', adapted to revolve in the frame ff on pivots p, the boards b, sliding ingrooves g, formed IOO on the inside of the revolving frame 1^ f, and the revolving frame 1' f, all combined substanthe catch c, all combined substantially as detially as described.

scribed. In witness whereof I have hereto set my 4. In a lesson board, the stationary frame, hand this 10th day ofJanuary, 1885.

5 ff, provided with chalk-box c h, catch c, soek- WILLIAM E. MGKENZIE.

et plates s 12, the frame r' f, revolving in such Witnesses stationary frame on pivots p, and the boards WM. E. BARTON, b, sliding in grooves y, formed on the inside of G. P. JACOBS. 

